The move will infuriate the US which has warned that a relaxation of the EU arms embargo to allow training would help China to work out ways of countering western military doctrine.

The People’s Liberation Army is the world’s largest armed forces at more than 1.25 million strong and is increasingly seen by the US as a major threat.

The ban on military cooperation is part of an arms embargo imposed by the US and EU countries in the wake of the Tiananmen Square crackdown in June 1989.

China has lobbied for a relaxation of the ban, specifically calling for cooperation on military training and education.

Some EU countries, led by France and Germany, sought to lift the ban several years ago but backed down in the face of a furious US response.

The US responded to the calls to lift the embargo by warning that any relaxation would have “serious consequences”.

It would give China access to “critical military ‘software’ such as modern military management practices, operational doctrine and training,” the Pentagon said in a 2005 report.

The Blair government firmly backed the US position banning all military cooperation and arms sales and no Chinese officers were trained at Sandhurst throughout Blair’s time as prime minister.

Britain had until now taken the lead on attempting to ensure that the EU suspension of military cooperation and the arms embargo held in place.

It has always previously taken the position that the existing suspension was not water tight enough and it was too easy for member states to get round the ban on military cooperation and arms sales.

The Conservatives demanded to know who had decided on the apparent change of policy, which they said put security at risk by giving the Chinese access to a wealth of detail on UK military doctrine.

“This is a critically important issue,” said Liam Fox, Shadow Defence Secretary. “We require urgent disclosure about whether the prime minister or the defence secretary knew about this and whether it represents a change in policy or plain incompetence with our national security.”

The MoD insisted it was complying with EU policy and stressed the firm British adherence to the arms embargo which banned sales of lethal weaponry to China.

“The UK fully complies with the EU arms embargo and the wider-ranging EU Code of Conduct on Conventional Arms, which deal with the sales of equipment,”

But the Conservatives said this did not address the key issue which was the suspension of military cooperation which was imposed alongside the arms embargo.

The precise wording of the EU ban makes clear it also affects military cooperation but despite repeated requests the MoD failed to address that issue.

The EU statement calls for the “interruption by the member states of the community of military cooperation and an embargo on trade in arms with China.”

Fox said the Conservatives had spoken to EU officials who said the ban on military cooperation did include training and “expressed surprise” that Britain should break ranks on the issue when it had previously taken the lead on enforcing military sanctions.